A variety of packages, including dispensing packages or containers, have been developed for personal care products such as shampoo, lotions, etc., as well as for other fluid materials.
A popular package design is the squeeze bottle or flexible container which is intended to be squeezed by the user to dispense the product. Such a container typically includes closure through which the product is dispensed. In some designs, the closure automatically closes the dispensing opening and also permits venting of air into the container to equalize the inside and outside pressures when the squeezing pressure is released from the container.
While some such prior art designs are functional, there are a number of disadvantages with such prior art designs. For example, some closures may require the fabrication and subsequent assembly of three or more separate pieces to form the closure.
Some closures do not dispense the fluid product as well as would be desired, and the structural components of the closure may tend to lose the required flexibility or resiliency characteristics that are desirable for continued, long-term operation.
Some types of closures are susceptible to accumulation and congealing of the fluid product at and around the dispensing orifice structure.
U.S. Pat. No. 4,728,007 discloses a resiliently deformable container having a discharge orifice equipped with a self-sealing dispensing valve in the form of a concave diaphragm formed of a resilient material that includes a generally straight line slit from which the fluid product can be dispensed. In operation, when the container is squeezed, a threshold pressure is exceeded to effect inversion of the diaphragm valve from its inwardly concave sealed position to an outwardly distended, convex, open position permitting discharge of the fluid product from the container. The patent describes the structure as inverting by a "snapthrough buckling" so as to pass through an unstable dead-center closed position by "snap-back buckling".
In many fluid dispensing applications, it would be desirable to provide an improved dispensing closure having advantages not found in the closure disclosed in the above-discussed U.S. Pat. No. 4,728,006. In particular, the use of a concave diaphragm valve which inverts by snap-through buckling of the type disclosed in the patent can cause the fluid product to be expelled in a sudden, and not easily controllable, discharge. Indeed, owing to the snap-through buckling action of the resilient diaphragm, the fluid product can be undesirably expelled in a "spitting"-like discharge. It can be difficult for the average user to gently discharge only a small amount of the fluid product. Thus, it would be desirable to provide an improved closure that has a substantially reduced tendency to "spit" out the fluid product and that can be relatively easily controlled with respect to the discharge of initially small amounts of the product.
The use of a concave flexible diaphragm of the type disclosed in the above-discussed U.S. Pat. No. 4,728,006 necessarily results in the discharge end of the closure being generally blunt with a recess. Thus, during the initial positioning and aiming of the container and dispensing closure, the precise point at which the fluid product will be discharged from the inverted flexible diaphragm can be somewhat difficult to judge for the average user. If, for example, it is desired to apply only a very small drop of product on the tip of one's finger, then the initially inverted closure diaphragm, being recessed, would necessarily be located some small distance away from the finger. Owing to the closure structure surrounding the recessed diaphragm, the exact location of the point where the fluid product will be discharged is not readily visualized. Thus, in many applications, it would be desirable to provide an improved closure wherein the point of fluid product discharge is readily observed and initially accessible to facilitate the more precise deposit of a very small amount of the fluid product at a given location.
It would also be desirable to provide such an improved dispensing closure structure with a suitable configuration for functioning, if desired, as an applicator. Then, during and after the discharge of the fluid product from the closure, the closure could be used to spread or otherwise engage the deposited fluid product.
It would also be advantageous to provide such an improved dispensing closure with a configuration that would quickly respond when pressure is applied to squeeze the container. The closure described in the above-discussed U.S. Pat. No. 4,728,006 requires a snap-through buckling movement of the diaphragm from an inwardly concave orientation to an outwardly convex orientation. Until this movement has occurred, the fluid product cannot be dispensed. In some applications, it would be beneficial if a closure could be made more sensitive to the applied squeezing pressure and could therefor function to discharge the fluid product with a reduced "lead time" required to actuate or deform the closure structure to the open position.
As previously noted, the resilient diaphragm valve disclosed in the above-discussed U.S. Pat. No. 4,728,006 is said to invert by snap-through buckling during operation. In some applications, a dispensing closure must be operated many thousands of times. Repeated and severe flexing of some resilient materials might eventually cause failure of the materials or loss of the desired resiliency. Thus, it would be beneficial to provide an improved dispensing closure which would operate with a reduced flexure movement and with reduced stresses so as to provide a relatively greater life cycle. The employment of an improved dispensing closure configuration that operates with reduced flexure and with reduced stresses would desirably permit the fabrication of the closure from other, and less expensive, materials that would otherwise be susceptible to tearing or other failure after a large number of operation cycles.
Further, it would be desirable to provide an improved dispensing closure for use with a squeeze-type package wherein the product flow out of the closure would be cleanly cut off or terminated when the squeezing pressure is released. Also, such an improved dispensing closure should desirably accommodate the dispensing of the fluid product when the container is either upright or inverted. Finally, such an improved dispensing closure should operate to discharge the fluid product without accumulating an undesirable amount of fluid product on the exterior of the closure.